The X-Ray Measurement of Residual Stress in Stainless Steel Used as Clothing Metal

Abstract

A stainless steel clad plate, consisting of a stainless steel plate and an other-kind-of-steel plate combined together by rolling, explosion or other technique, becomes equipped with both the properties of the clothing metal and of the base metal. Since reinforcing the base metal by clothing it with stainless steel to raise its resistance against corrosion and pressure has come to be in vogue in recent years for various purposes, the problems regarding the clothing metal have begun to attract attention, particularly with respect to the residual stress on its surface and the internal distribution of stress in it.
In the present paper is presented the result of experiment made concerning the residual stress in the stainless steel clad plate which had been subjected to hot rolling in the clothing. Two specimens have been used, the SS41 base metal clad with the SUS28 stainless steel plate (RA material), and the SB42 base metal clad with the SUS38 stainless steel plate (RF material).
The residual stress released by cutting the steel plates to clothe the base metal of RA and RF materials into small blocks was found to be within the range of ±6kg/mm². The X-ray measurement of stress on the surface of the clothing SUS28 stainless steel plate and of stress distribution in its depth revealed that ca. 20kg/mm² of compressive residual stress was generated in it, and that ca. 15kg/mm² of tensile residual stress was generated in the SS41 base metal.
This difference is considered to be due to the difference between SUS28 and SS41 in thermal expansion coefficient, and it is considered that there was plastic deformation of SUS28 while it was subjected to cooling in air. On the other hand SUS38 and SB42 were approximately equal in coefficient value, and so no residual stress was detected in RF material.
From the result of measurement of the residual stress distributed in the plates and of the width of the diffraction line in them, it is supposed that the combination of the steel plates by rolled clothing is effected within very thin scopes of their respective layers.